Two Kinds Of Quantum Steering Scenarios In Tripartite Quantum Systems

Quantum steering refers to the fact that the measurement of particles in one subsystem can influence the states of particles in the other subsystems.It is a kind of quantum feature between entanglement and Bell non-locality.Because of the asymmetry of quantum steering,it plays an important role in many aspects.In this dissertation,two types of quantum steering scenarios are introduced for a tripartite quantum system,named "one-sided device-independent steering" and "two-sided device-independent steering".Each of them contains two levels according to the separability of the local hidden states and the independence of the local hidden variables,respectively.At the same time,the mathematical definitions of these steering scenarios and the methods of judging whether a quantum state is steerable are given.Finally,the robustness of steering in a tripartite quantum system is introduced and its properties are given.This paper is divided into three chapters,the specific contents are as follows:In the first chapter,we introduce the background and research status of quan-tum steering,and list some basic concepts and definitions of quantum information.In the second chapter,we introduce the steering scenarios in a tripartite quan-tum system and give the mathematical definitions of these cases.Based on giving the mathematical definitions of these steering scenarios,we drive some necessary and sufficient conditions for a state to be unsteerable and prove some sufficient con-ditions for a state to be steerable are also established.At the same time,we give several examples in this chapter.In the third chapter,we introduce the robustness of steering in tripartite quan-tum system and prove some properties of the robustness.